Much interest has been expressed recently in providing voice and data local loop services via wireless systems. Wireless digital subscriber line (wDSL) systems are systems that connect subscribers to a public switched telephone network (PSTN) and/or other networks, such as the Internet, using radio signals to exchange information, as a substitute for copper wiring, over all or part of the connection between the subscriber and the switch and/or gateways and routers. Wireless local loop (WLL) systems have been installed in various locations to date, primarily third world or developing nations where the cost to establish a copper wire infrastructure for local loop services is very high. In more industrialized locations such as North America, including locations where a copper wire infrastructure already exists, great interest in wDSL also exists to provide competition in local access services.
Many WLL or wDSL systems developed and/or proposed to date build upon techniques and technologies developed for cellular mobile systems, including analog cellular and GSM or CDMA cellular. Such systems have proven to be very successful to date at providing mobile wireless communications and much development has been performed with respect to their technologies.
In such systems, control signals are generally transmitted between subscriber station and base station either through a random access channel (RACH), which operates under an Aloha-like random access protocol which is subject to collisions and other failures, or dedicated traffic channels (DTCHs), wherein system resources are reserved for the communication between the two devices. However, the design of RACH and DTCH in such cellular systems were driven by the typical operating characteristics of cellular telephones for voice communication, i.e.—most phones spend a great deal of their time idle and most connections, when they occur, last an average of three minutes. Channel setup thus occurs relatively infrequently and such a setup requires only a small amount of connection time/bandwidth relative to the typical three minute duration of the connection.
The present inventors have determined however, that while wDSL systems based upon mobile cellular technologies can provide reasonable voice performance, they do not provide bandwidth efficiencies that will be required for wDSL systems which are widely deployed and which provide voice and data services. RACH channels will quickly be saturated as numbers of users escalate and use of traffic channels for control signals will consume valuable transmission capacity that will be otherwise required for servicing users. Further, unlike voice, data transmissions are typically bursty and occur at many random times and conventional, cellular-type, set up requirements are excessive relative to the typically brief, bursty data transmissions.
It is therefore desired to have a system, apparatus and method to provide digital subscriber line services via wireless communications which better lends itself to large deployments.